SW M25 Relief

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Vierwielen
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Re: SW M25 Relief

Post by Vierwielen »

JammyDodge wrote: Mon Sep 06, 2021 09:54 I don't know whether this data exists already:
Wouldn't it be a good idea to do an extensive traffic study with the M25, using ANPR cameras
Placing them at all entrances and exits to the M25 as well as along each stretch between junctions, over 12-24 months, you could figure out exactly where traffic is coming from and going on the M25.
This data would probably be of great use for planning future expansions for Express and Local lanes and would be more detailed than just traffic counts along sections of the M25
Ideally this could be coupled with a knowledge of the residence of the registered keeper, but the GDPR implications are enormous. It might be possible however to gather this data from the 2021 census figures, though it would have to be framed in such a way as to anonymise the data.
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Re: SW M25 Relief

Post by JammyDodge »

Vierwielen wrote: Tue Sep 07, 2021 21:57
JammyDodge wrote: Mon Sep 06, 2021 09:54 I don't know whether this data exists already:
Wouldn't it be a good idea to do an extensive traffic study with the M25, using ANPR cameras
Placing them at all entrances and exits to the M25 as well as along each stretch between junctions, over 12-24 months, you could figure out exactly where traffic is coming from and going on the M25.
This data would probably be of great use for planning future expansions for Express and Local lanes and would be more detailed than just traffic counts along sections of the M25
Ideally this could be coupled with a knowledge of the residence of the registered keeper, but the GDPR implications are enormous. It might be possible however to gather this data from the 2021 census figures, though it would have to be framed in such a way as to anonymise the data.
Possibly, but If you where to take a residence, you would only take the 1st half of a postcode (or even just the 1st letters for a general region) to anonymise the data

Personally, I think that it is easier, privacy-wise, to store the plate when a vehicle enters. Then log a trip from Jx - Jz when the vehicle exits and delete the plate from the database
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Re: SW M25 Relief

Post by Peter Freeman »

jackal wrote: Tue Sep 07, 2021 16:55 Yes, of course there's a lot of braiding. But my point was that you would need a lot more braiding still to remove weaving on the outercarriageways as well, which seemed to be the thrust of your previous post.
No, that wasn't exactly my intent. In the model I was thinking of, there wouldn't be inner and outer carriageways between J14A and 15, simply a D6 mainline as far north as the stack, same as now (unless loading on the runway spans requires such a split). But in my model the combined J14/14A northbound on-ramp would first branch right to merge with the mainline (for M4 destinations), but also continue separately northwards to J15 for M25 destinations. At J15 it would bridge over the M4 westbound low-level on-ramp, then over the M4 mainline, then under the high-level stack connectors that occupy the NW quadrant, and then merge with the M1 mainline northbound. The four levels of the stack do support such a configuration. An equivalent arrangement would serve in the anti-clockwise direction. Picture it in plan view as a stack with its currently-vacant enclosed spaces traversed by N-S bypass lanes.

You could say this still has an outer carriageway, but it's really a long on-ramp, and effectively a braid. Weaving is not totally eliminated. The model's advantage is that it could provide more than 3 (or ALR 4) M25 lanes through J15. Existing lateral clearances each side of M25 do not otherwise allow that.

On reflection, we probably don't need >4 M25 lanes through J15. And although my new bridges within the stack footprint are feasible, they total more than the HAL design's additional bridges. So I suppose I'll withdraw my idea!
I really like the HAL design but it has tight weaving spaces on the outercarriageways.
Like it: I agree. With J14/14A traffic merging from the right, only a small proportion of vehicles would need to lane-swap, and probably only by one lane, and they have 1km to do it in. Just ok.
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Re: SW M25 Relief

Post by jackal »

The design you outline is similiar to HAL's single junction designs such as JD2, JD3 and JD6 (see plans on previous page). The main difference is that you have the braiding near J15 rather than J14. The reason for putting the complexity at J14 is rather clear given anything at the J15 end has to go under a runway and taxiways! But even if they weren't to be there I'm sure it would be easier to thread the various slips through a rebuild of J14 that's designed to take them, as per the JD designs, rather than bolt them on to an existing stack with a railway going through it.

The HAL designs generally have the feature of being essentially long sliproads. That is, once you go from mainline to outercarriageway, you cannot get back. So as I say, similar to your suggestion but in reverse.

Once upon a time I used to say long slip roads weren't true C/D lanes, as C/D lanes are supposed to split local and express traffic and to do that they have the feature of connections to/from the mainline at both ends. Here the split is between different types of strategic traffic (M4/M25) so there is no need for outercarriageways to link to the M25 mainline at both ends. Other examples of 'long slip roads' are M8/M74/M77 and the forthcoming M2/A2/A289/LTC section; examples of 'true C/D lanes' are M60 J6 to J8 and M20 J5 to J6. I've long accepted that you have to call both types C/D lanes as everyone else does, and they're clearly close relatives.

PS - 6 lanes for the mainline may not be over the top in the long run. HE insisted on futureproofing under the runway tunnel to allow 4 lanes for outercarriageways and 6 for inner carriageways, plus HS for both!
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Re: SW M25 Relief

Post by ChrisH »

JammyDodge wrote: Wed Sep 08, 2021 00:31
Vierwielen wrote: Tue Sep 07, 2021 21:57
JammyDodge wrote: Mon Sep 06, 2021 09:54 I don't know whether this data exists already:
Wouldn't it be a good idea to do an extensive traffic study with the M25, using ANPR cameras
Placing them at all entrances and exits to the M25 as well as along each stretch between junctions, over 12-24 months, you could figure out exactly where traffic is coming from and going on the M25.
This data would probably be of great use for planning future expansions for Express and Local lanes and would be more detailed than just traffic counts along sections of the M25
Ideally this could be coupled with a knowledge of the residence of the registered keeper, but the GDPR implications are enormous. It might be possible however to gather this data from the 2021 census figures, though it would have to be framed in such a way as to anonymise the data.
Possibly, but If you where to take a residence, you would only take the 1st half of a postcode (or even just the 1st letters for a general region) to anonymise the data

Personally, I think that it is easier, privacy-wise, to store the plate when a vehicle enters. Then log a trip from Jx - Jz when the vehicle exits and delete the plate from the database
This dataset does already exist. ANPR cameras hash numberplates each time they are seen, but using the same formula. So an individual vehicle's trip on and off the strategic network can be seen.

This is how the info in the slide deck I linked on the previous page is generated.

This info also acts as inputs to the traffic models used by authorities and consultancies.
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Re: SW M25 Relief

Post by ChrisH »

Peter Freeman wrote: Tue Aug 24, 2021 05:09 The M25 J10-16 clockwise congestion is so chronic that, it appears to me, even a small (<10%) traffic reduction would be worthwhile.

My original thoughts on the M3-M4 link centred around a Bracknell bypass. That's a major project - everything else in my OP is just discrete incremental improvements. My first Bracknell thought was an HQDC half-ring around the SW of town. But then, while playing the directions game on google maps, I noticed that, at the very worst times of day, an alternative avoiding the town is already occasionally suggested. So we don't have to move this topic to the Fantasy forum: all that is required is to improve that existing de-facto bypass.

The route begins at the junction A322/B3430. It runs westwards along B3430 Nine-Mile Ride as far as Old Wokingham Road. It then runs northwards along Old Wokingham Road and Peacock Lane to re-join A329. A short length of new construction would tie it smoothly into the A329(M) GSJ.

The conventional way through Bracknell measures 4 miles and takes between 7 and 13 minutes. The bypass route (unimproved) measures 5 miles and takes 8 minutes. Dualled, shortened and properly connected, it would take only 4 minutes.

Of course, I don't know the context of my route. It looks (on google earth) ideal: almost undeveloped, enough space, hardly any obstructions. The dualling need not be quite HQDC standard, so not expensive. I suppose it would meet the usual NIMBY resistance - is there anything there that I don't know about? I have noticed the nearby golf course ... !
I am familiar with the routes around and through Bracknell, and take them often. The Nine Mile Ride to the south of the town has very uneven horizontal and vertical alignments and wouldn't be suitable for heavy traffic. Any encroachment into Swinley Forest would also be fiercely resisted.

I have sketched up in this slide deck here my preference for an A329(M) extension down to the M3. It comprises:

- New all-purpose link from the awful Jennett's Park roundabout to the current southern terminus of A329(M), and restoration of continuous dual carriageway past it
- Closure of Doncastle Road roundabout
(This provides A329(M) extension as far as central Bracknell)
- Then drop into a 3km tunnel from the Twin Bridges roundabout down to the Coral Reef / Nine Mile Ride junction. The junctions on the main road are only 600-800m apart which I think is insufficient to surface a tunnel or put any consecutive grade separation in. The tunnel could be made shorter if the southern junction(s) could be grade separated.
- Close the A332 weird half-roundabout and redirect A332 along the old (eastbound) carriageway of A322, as far as A30
- One new carriageway needed parallel to current westbound A322 carriageway
- New bridge over A30, current A322 and railway with decent standard all-movements sliproads
- Current A322 from M3 to A30 becomes local access route
- New direct slips to join M3 towards London

The overall effect of this would be a motorway link from the M4 to M3 with only three intermediate junctions (the current A329/B3408 junction, a split junction either side of Bracknell, and one for A30 and local routes). It would relieve the local roads of all strategic traffic and allow space reallocation to walking, cycling and public transport. And it would generate a degree of relief for the very busy M25/M4 sections to the east.
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Re: SW M25 Relief

Post by thatapanydude »

I would link up Twickenham to Cranford (M4 j3) by building a D2 dual carriageway roughly along Crane Park (red line picture below) which can help provide a decent quality inner London link between the A40 (M40) and A316 (M3) that should take some traffic off the M25 while helping cross London travel.
Attachments
A40 to A316 link.gif
A1/A1(M) >>> M1
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Re: SW M25 Relief

Post by Peter Freeman »

Micro The Maniac wrote: Tue Sep 07, 2021 10:51
ChrisH wrote: Tue Sep 07, 2021 09:03 There was a very useful presentation given to stakeholders back in 2018 - slides are online here.
Interesting (Slide 10):
Conclusions of study to date:
 Directly adding capacity to the M25 SWQ not feasible

Recommendation:
 Instead of widening the existing M25, attention should be given to reducing traffic demand and providing parallel capacity to relieve the pressure on the M25.
That slide deck is actually quite good. It contains some useful traffic data and analysis. A bit waffly, and for political correctness had to delve into rail and active travel. Much as I like public transport (and riding my pushbike for leisure), railways are no more a substitute for decent roads than roads are for railways. But I ultimately have to agree with the session's conclusions.

"Directly adding capacity to the M25 SWQ not feasible" is rather overstating things. It (and eventually all M25 non-ALR bits) should be ALR'ed. Retain single lane drops at most junctions (as generally now). Re-work J14/14A, including proper braiding - either as part of Heathrow expansion (so it has to wait), or standalone if Heathrow doesn't happen (so it could be done better and sooner). Minor interchange improvements. But that's it for M25.

The session's main conclusion is that relief must come from improvements to local roads and strategic roads, inside and outside the orbital. Back to where we started!

I favour improvements to strategic roads for M25 relief, rather than local roads, as the latter just encourages rat-running. There are plenty of good suggestions mapped out, far exceeding the A404 and A329 that this topic began with. Even an A406 tunnel.
Last edited by Peter Freeman on Fri Sep 10, 2021 02:39, edited 1 time in total.
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Re: SW M25 Relief

Post by Micro The Maniac »

ChrisH wrote: Wed Sep 08, 2021 16:19 I am familiar with the routes around and through Bracknell, and take them often. The Nine Mile Ride to the south of the town has very uneven horizontal and vertical alignments and wouldn't be suitable for heavy traffic. Any encroachment into Swinley Forest would also be fiercely resisted.

I have sketched up my preference for an A329(M) extension down to the M3. It comprises:
{snip}

The overall effect of this would be a motorway link from the M4 to M3 with only three intermediate junctions (the current A329/B3408 junction, a split junction either side of Bracknell, and one for A30 and local routes). It would relieve the local roads of all strategic traffic and allow space reallocation to walking, cycling and public transport. And it would generate a degree of relief for the very busy M25/M4 sections to the east.
While following the path of the A322 is the obvious solution, I still maintain that (broadly) following the A3095/A331 alignment would be a better strategic option - although admittedy the Hog's Back and the Surrey Hills AONB limit the southern options!
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Re: SW M25 Relief

Post by Peter Freeman »

Most of the corner-cuts that we've discussed are known to, and used by, locals. And they're used by them at the appropriate times, according to likely congestion. They're probably much less used by non-locals, except for those who are following satnavs.

Satnav usage is increasing, and will become the norm. This will significantly affect route choice, and will make even small improvements to alternative routes exploitable and beneficial. This is why, for example, GSJ'ing Bisham roundabout will attract traffic to the A404, even without fixing that route's other defects. Similarly, even an at-grade and slightly sub-standard Bracknell SW bypass would pay off in a satnav environment, but would be largely unknown and therefore unexploited otherwise.

Interestingly, there's an article along these lines in the current edition of Highways Magazine -

https://edition.pagesuite.com/html5/rea ... 217f71d22c
Last edited by Peter Freeman on Fri Sep 10, 2021 06:32, edited 1 time in total.
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Re: SW M25 Relief

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Peter Freeman wrote: Thu Sep 09, 2021 05:24 I favour improvements to strategic roads for M25 relief, rather than local roads, as the latter just encourages rat-running. There are plenty of good suggestions mapped out, far exceeding the A404 and A329 that this topic began with. Even an A406 tunnel (yeah, right - we can't even underpass some NCR traffic lights!).
Maybe we need a new radial, built as a HQDC. For example, one connecting, Reading (M4 J10) to Maidenhead (M20 J5), going via Bracknell, Guilford, Crawley and Tonbridge (route will be able to avoid most of the AONBs and SSSIs, with the only AONB being crossed at the A3/A31 junction (Hog's Back for about 3 miles)

Here is a very rough map:
M25 bypass-min-min (1).jpg
I selected a north/eastern bypass for Bracknell because it would be able to avoid the SSSI over Swinley Forest and would be easier to connect up to the A404, via a spur, which I think provides better connections for what would be, effectively a M25 bypass
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Re: SW M25 Relief

Post by KeithW »

The core issue here I am afraid is the London centric nature of the English road network particularly south of a line between Peterborough and Birmingham. The original solution for this problem was the Ringway system a plan which was flawed but had elements in it that were worth pursuing. Ringway 1, the inner motorway box that all the radials would extend to was always going to be too disruptive but the idea of outer ring routes as exemplified in the pre war North Orbital Road had its merits however government shied away from the cost of building both Ringway 3 and 4 so we ended up with an amalgam of the two in the M25 which was overwhelmed by traffic pretty much from the moment it opened. In no small part because it had to deal with the issues the original planners had seen with the mixing of local and long distance traffic.

In my opinion what is needed is more major cross country roads that avoid London and the South East as far as possible. The M40 was a good start that coupled with the M42/A42 allowed traffic from the North to get to South West without touching London. Alas the M42/A42 was built on the cheap and is itself very congested. The same is true of pretty much all the cross country roads from East to West.

This is why I supported the idea of an Oxford Cambridge Expressway that would allow traffic from the North and East Anglia including Felixstowe to get to Oxford, the Thames Valley, Wales and the South West without using the congested roads around London. Alas that soon morphed into a developer lead mechanism to allow growth along the Oxord/MK/Cambridge Corridor.

If you look that those cross country roads which do exist they are not of the highest quality and I suspect have limited spare capacity. The A421/A428 from Cambridge to MK is a decent enough road but leaves you battling through MK negotiating what seems like an endless number of roundabouts before becoming an unimproved S2 to the A43.

The A34 from the M40 to the M4 is massively overloaded, I have proposed in the context of the Oxford Cambridge Expressway a proposal proposal to upgrade offline the A420 to Swindon and the M4 which would allow traffic from the West and South West to avoid the congested roads around Oxford .

The next major bottleneck if you are heading for the South West, specially in summer is the Bristol area. Head down the M5 and its not unusual to spend an hour in the crawl from J14 to J20. So again in the spirit of relieving known traffic hotspots I would suggest the idea of a South Bristol Relief Road from M4 J18 to the A38 near Felton.

None of this will ever happen of course but I can dream.
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Re: SW M25 Relief

Post by Vierwielen »

JammyDodge wrote: Fri Sep 10, 2021 01:23
Peter Freeman wrote: Thu Sep 09, 2021 05:24 I favour improvements to strategic roads for M25 relief, rather than local roads, as the latter just encourages rat-running. There are plenty of good suggestions mapped out, far exceeding the A404 and A329 that this topic began with. Even an A406 tunnel (yeah, right - we can't even underpass some NCR traffic lights!).
Maybe we need a new radial, built as a HQDC. For example, one connecting, Reading (M4 J10) to Maidenhead (M20 J5), going via Bracknell, Guilford, Crawley and Tonbridge (route will be able to avoid most of the AONBs and SSSIs, with the only AONB being crossed at the A3/A31 junction (Hog's Back for about 3 miles)

Here is a very rough map:
M25 bypass-min-min (1).jpg

I selected a north/eastern bypass for Bracknell because it would be able to avoid the SSSI over Swinley Forest and would be easier to connect up to the A404, via a spur, which I think provides better connections for what would be, effectively a M25 bypass
Maidstone surely, not Maidenhead.
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Re: SW M25 Relief

Post by JammyDodge »

Vierwielen wrote: Sat Sep 11, 2021 20:30
JammyDodge wrote: Fri Sep 10, 2021 01:23
Peter Freeman wrote: Thu Sep 09, 2021 05:24 I favour improvements to strategic roads for M25 relief, rather than local roads, as the latter just encourages rat-running. There are plenty of good suggestions mapped out, far exceeding the A404 and A329 that this topic began with. Even an A406 tunnel (yeah, right - we can't even underpass some NCR traffic lights!).
Maybe we need a new radial, built as a HQDC. For example, one connecting, Reading (M4 J10) to Maidenhead (M20 J5), going via Bracknell, Guilford, Crawley and Tonbridge (route will be able to avoid most of the AONBs and SSSIs, with the only AONB being crossed at the A3/A31 junction (Hog's Back for about 3 miles)

Here is a very rough map:
M25 bypass-min-min (1).jpg

I selected a north/eastern bypass for Bracknell because it would be able to avoid the SSSI over Swinley Forest and would be easier to connect up to the A404, via a spur, which I think provides better connections for what would be, effectively a M25 bypass
Maidstone surely, not Maidenhead.
I vaguely remember being quite drunk when I made this, probably why, lol
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Re: SW M25 Relief

Post by Peter Freeman »

^ Oh, I see. Then I suppose that, when you're drunk, 'radial' must sound rather like 'orbital' ... ?
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Re: SW M25 Relief

Post by Gav »

Micro The Maniac wrote: Tue Aug 31, 2021 08:38
Gav wrote: Sun Aug 29, 2021 11:11 That motorway without the hardshoulder there is less room for any out of the ordinary issues
You mean like:
  • Stopping for a wee
  • Changing a baby's nappy
  • Swapping drivers
All three of these were observed yesterday on the two-lane bit of the M3... all within a few hundred yards of Winchester Services (admittedly not the best on the network, but...)
you do know that these wombles will still do what they do... but in the refuge areas - laybys look at those nice laybys... no body in them... until of couse a wagon or car needs to get in.. hardshoulders are there for a legitimate reason, and removal of said hard shoulders is a massive retrograde step. just be done with it... remove the hardshoulders and call it the A3...
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Re: SW M25 Relief

Post by Micro The Maniac »

Gav wrote: Sun Sep 12, 2021 13:08 just be done with it... remove the hardshoulders and call it the A3...
You do realise that there is already a 70mph D3 (without hardshoulders) called the A3?
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Re: SW M25 Relief

Post by Vierwielen »

Micro The Maniac wrote: Sun Sep 12, 2021 13:47
Gav wrote: Sun Sep 12, 2021 13:08 just be done with it... remove the hardshoulders and call it the A3...
You do realise that there is already a 70mph D3 (without hardshoulders) called the A3?
... which every workday evening becomes a D2 traffic jam (theoretically 50 mph :pig: ) in the vicinity of Guildford
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Re: SW M25 Relief

Post by Phil »

Herned wrote: Sun Sep 05, 2021 21:40
Scratchwood wrote: Sun Sep 05, 2021 21:30 My issue with the toll is that it penalises people going one way around London on the M25/A282 route, but not the other

Imagine if the M60 had a toll section on one small section of it, traffic volumes around the M60 would be distorted to avoid that section.
Does it really though? There can't be many journeys which result in people choosing to go one way rather than the other - M23 to A1 or A10 perhaps it might swing it for one way or the other, but for most journeys the toll is annoying but far better than going around the longer way or through London. The numbers of actual journeys made every day which have a genuine choice must be a minute proportion of the total
More than you might think!

For starters anyone coming from Kent (which includes huge volumes of HGVs to / from mainland Europe) heading for the Midlands / North west can either go via the South West quadrant to the M40 / M1 for free or via Dartford with its tolls.

Similarly those in Surrey / Sussex and Hampshire (A3) Corridor) heading for Cambridge, Norwich (or Freight heading to Felixstowe) has a choice of going via Heathrow for free or via Dartford with a toll.
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Re: SW M25 Relief

Post by Chris5156 »

Phil wrote: Mon Sep 13, 2021 02:03
Herned wrote: Sun Sep 05, 2021 21:40
Scratchwood wrote: Sun Sep 05, 2021 21:30 My issue with the toll is that it penalises people going one way around London on the M25/A282 route, but not the other

Imagine if the M60 had a toll section on one small section of it, traffic volumes around the M60 would be distorted to avoid that section.
Does it really though? There can't be many journeys which result in people choosing to go one way rather than the other - M23 to A1 or A10 perhaps it might swing it for one way or the other, but for most journeys the toll is annoying but far better than going around the longer way or through London. The numbers of actual journeys made every day which have a genuine choice must be a minute proportion of the total
More than you might think!

For starters anyone coming from Kent (which includes huge volumes of HGVs to / from mainland Europe) heading for the Midlands / North west can either go via the South West quadrant to the M40 / M1 for free or via Dartford with its tolls.

Similarly those in Surrey / Sussex and Hampshire (A3) Corridor) heading for Cambridge, Norwich (or Freight heading to Felixstowe) has a choice of going via Heathrow for free or via Dartford with a toll.
Sure, there are journeys you can think of that have a choice between going one way around the M25 or the other. They are inevitably trips between opposite sides of the capital that involve making a half-orbit of the M25. But Herned's point is that the amount of traffic on the SW quadrant of the M25 that is actually doing that is very small. And he is right.

The point has already been made upthread that only 14% of journeys on the M25 are people starting and ending their trip outside London. Not all those will be making a trip that makes a full half-orbit. Many will be making a smaller hop, like Sevenoaks to Guildford or Slough to Gatwick.

It would be charitable to say even half of the journeys that are truly bypassing London are making a half-orbit, and would therefore be able to choose freely between Dartford or going the opposite way, but even if we do assume that, you are left with 7% of journeys having the choice of free vs toll.

In other words, the number of journeys that genuinely have a choice about whether they go via Dartford, and which might therefore unnecessarily load the west side of the M25, is small, and abolishing the Dartford toll would not materially affect congestion levels on the SQ quadrant.
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